.menu {
  height:90vh;
}
.submenu {
  background:red;
  padding:0;
  margin:0;
  border:0;
}
@media screen and (min-width:1200px){
  .hide {
    background:red; 
    height:15px;
    width:15px;
    float:right;
    margin-right:1rem;
    margin-top:35rem;
  }
}
@media screen and (max-width:900px){
  .hide {
    background:red; 
    height:15px;
    width:15px;
    float:right;
    margin-right:1rem;
    margin-top:25rem;
  }
}


@keyframes tohide
{
  0%   {left:0px; top:0px;}
  100%  {left:-250px; top:0px;}
}